FTP

The FTP integration backs up directories from an FTP server and restores snapshots to an FTP server. It supports plain FTP and FTPS (FTP with TLS), with FTPS enabled by default. SFTP (SSH File Transfer Protocol) is a different protocol handled by the SFTP integration.

The integration includes two connectors:

Installation

The FTP integration is distributed as a Plakar package.

$ plakar pkg add ftp

$ plakar pkg show

$ plakar pkg build ftp

$ plakar pkg add -allow-unsigned ./ftp_v1.0.0_darwin_arm64.ptar

$ plakar pkg show

To list, upgrade, or remove the package, see managing packages guide.

Transport security

The connector encrypts the connection with FTPS by default. The tls option selects how TLS is negotiated:

With TLS enabled, the connector requires TLS 1.2 or later and verifies the server certificate against the system’s trusted certificate authorities and the server hostname. Setting tls_insecure_no_verify=true skips this verification, for example for a server using a self-signed certificate.

Plain FTP must be requested explicitly. The connector refuses tls=none unless tls_insecure_no_verify=true is also set to acknowledge that credentials and data travel unencrypted.

$ plakar source set ftp_src tls=none tls_insecure_no_verify=true
$ plakar destination set ftp_dst tls=none tls_insecure_no_verify=true

Configuration

Both connectors address a directory on the FTP server with an ftp:// URL. Credentials can be given in the URL or as separate options.

Backup flow

flowchart LR

subgraph Source["FTP Server"]
  FS["/pub/somedirectory"]
end

Plakar["Plakar"]

Via["Retrieve data via
FTP source connector"]

Store["Kloset Store"]

FS --> Via --> Plakar --> Store

Restore flow

flowchart LR

Store["Kloset Store"]

Plakar["Plakar"]

Via["Push data via
FTP destination connector"]

subgraph Destination["FTP Server"]
  FS["/upload"]
end

Store --> Plakar --> Via --> FS

Shared configuration

The following options apply to both source and destination connectors. They are set with plakar source add or plakar destination add, and changed with plakar source set or plakar destination set.

Destination configuration

The following option is available to the destination connector, in addition to those in Shared configuration.

Restore behaviour

Restore sets the permissions of each restored file and directory, including the setuid, setgid, and sticky bits, using the SITE CHMOD command. The destination directory itself keeps its existing permissions. File ownership is not restored.

Restored files are written only inside the destination directory. A snapshot entry whose path would resolve outside it, for example through .. components, is reported as failed and skipped.

Example

Back up a remote directory:

# Configure a source pointing to the remote FTP directory
$ plakar source add ftp_src ftp://ftp.example.org/pub/somedirectory

# Back up the remote directory to a Kloset store on the filesystem
$ plakar at /var/backups backup "@ftp_src"

Restore a snapshot to a remote directory:

# Configure a destination pointing to the remote FTP directory
$ plakar destination add ftp_dst ftp://ftp.example.org/upload

# Restore a snapshot to the remote FTP directory
$ plakar at /var/backups restore -to "@ftp_dst" <snapshot_id>

Limitations and scope

Files that are created, updated or deleted during a backup can leave the snapshot reflecting different points in time for different files. For highly dynamic paths, quiesce the workload or back up from a read-only replica.

Permissions on servers without SITE CHMOD

SITE CHMOD is a common extension rather than part of the core FTP standard (RFC 959). On a server that lacks or refuses it, such as most Windows servers, every restored file and directory is reported as failed, even though the files are written. Earlier versions of the FTP package did not set permissions, so restores to such servers start reporting failures after upgrading to v1.1.3. Set skip_permissions=true on the destination to restore without setting permissions.

See also

• SFTP / SSH